Long Wire Antenna

In 2005 I moved to town and into a house in a wooded area. The back yard was non existent, but a large deck had been built on the rear of the house and it overlooked a heavily wooded creek bottom.

This lovely location wasn't so lovely from the antenna standpoint. After cogitating on antenna posiibilities I came back to the ancient and irrestible long wire with a radial(s). However these can be hard to match especially if they're close to a half wave on the bands of interest. This conclusion was realized before my discovery of
Steve Yates, AA5TB, excellent treatise on matching half waves.

Matching an end fed halfwave has been considered difficult due to the high input inpedance. It's approximately 4000 - 5000 ohms and apparently some past tuner designs have had difficulty matching that to a 50 ohm feedline. Having proved the ease and efficiency of bow and arrow launching with prior long wires, I decided to give one another try. The bow would launch it high over the trees over the gully out back. Here's another way to get a long wire way up in the air.

In doing some research before hand I uncovered this tidbit on the Elecraft Reflector.

"In the article "Taming the End-Fed Antenna" ("The Antenna File", RGSB, pg 118) Alan Chester (G3CCB)(SK) proposed a solution for the high impedance of a 1/2 wave, end fed antenna. Mr. Chester rationalized that there might be some impedance friendly length of wire usable for an end-fed antenna - near 1/2 wave - that didn't present the tough-to-tune, high impedance load on a select set of bands. In short, he proposed wire lengths in the 1/8 - 3/8 or 5/8 - 7/8 wavelength range, staying away from the 1/2 wave length (or multiples thereof)."

Aha! Here was something I could grasp. Whipping up a spreadsheet I set about calculating wavelength vs wire lengths for 160 thru 10M. I had a large remnant of my 322 foot doublet , left over from the household move. Unrolling and measuring showed it to be 226 feet long. The spreadsheet determined that it should work resonably well. It did, especially on 80, but only fairly so on 15M. In retrospect I think part of the problem on 15 may have been rf in the shack. I was especially pleased that it worked "like gangbusters" on 80. With it I as able to do fairly well on the Tuesday Night 80M Fox Hunts. Other than the little difficulty on 15M it loaded and worked well on all other bands, even 160..

Considering an antenna as a system, I added a 100 foot radial, across the deck, down a post, and under the trees, and used an SGC-239 autotuner at the point of entry into the house, which was through a sliding glass door opening onto the deck.

My good ham radio pal Steve Miller, NěSM, and I spent a few hours putting this monster up. Launching it didnt require much time, but finding the arrow did. I had used flourescent fishing line in the reel hoping it would be easy to see in the trees. It wasnt as easy to follow above the trees as we had hoped. The canopy of the Oak-Hickory climax forest was too dense to see more than a short section of line at a time.

We entertained the locals on the repeater as we stumbled around in the woods using hand helds to communicate. It wasnt until the antenna was secured to the deck and a tree near the creek that we realized we should have been simplex as we were much closer to each other than we were the repeater!

So if you want to try a long wire as a multiband antenna, bring up the spreadsheet and try some different lengths before the work of erecting it. The time spent will pay dividends. If you are going to operate on one band, see AA5TB's web page for matching those.

Good luck and have fun.

Revised 2 Dec 2012
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